Perhaps you should try some spelling variations:
danh yen » danh tuyen, dan huyen, danh kien
xach tay » canh tay
cac tac » cac toc, cac bac, cac dac
yen cua » ben cua, gen cua, men cua
sach tu » sach thu, cach tu, sach ty
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va
va danh » va dinh, va dan, va hanh
cua te » cua tu
tac va » tac da, tac xa, tuc va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te ((xach tay) or (sach tu)) nang cao hoi. ((hieu va) OR (hieu qua)) cac tac va danh yen cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((xach tay) OR (sach tu)) nang cao hoi. ((hieu va) OR (hieu qua)) cac tac va danh yen cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((xach tay) or (sach tu)) nang cao hoi. ((hieu va) OR (hieu qua)) cac tac va danh yen cua te".
• Adding a wildcard symbol may retrieve word variants: te ((xach tay) or (sach tu)) nang cao hoi. ((hieu va) OR (hieu qua)) cac tac va danh yen cua te*.